This invention relates to a vehicular internal combustion engine with a subsidiary transmission and more particularly to an improved engine, transmission construction and an improved method for lubricating a transmission.
A type of vehicle that is currently enjoying great popularity is the balloon tired off the road vehicle designed to handle primarily a single rider. These vehicles may have either two, three or four wheels and are generally powered by a motorcycle type power plant that includes an engine and a change speed transmission within the crankcase of the engine. However, such driving arrangements do not offer sufficient numbers of forward gears for off the road use and, furthermore, such transmissions do not normally include a reverse. Therefore, it has been the practice to mount an auxiliary transmission at one side of the crankcase which auxiliary transmission contains additional forward gears and/or a reverse gear. However, the engine and transmission assembly is normally positioned between the rider's legs and the addition of a further transmission to one side of the crankcase can significantly and undesirably increase the width of the power plant and make the riding position uncomfortable.
It is, therefore, a principal object of this invention to provide an improved and compact transmission arrangement for an off the road vehicle.
It is a further object of this invention to provide an improved and compact auxiliary transmission in combination with an engine crankcase positioned primary transmission.
It is a still further object of this invention to provide a compact power unit for a vehicle.
When using an auxiliary transmission of the type as aforenoted, it is desirable to insure that the auxiliary transmission is adequately lubricated. This is particularly true if the auxiliary transmission also includes a final drive for driving a drive shaft to power the vehicle. Although such lubrication can be provided by incorporating a separate lubricant reservoir in the auxiliary transmission, this further adds to the amount of lubricant required for the complete system and adds to the servicing required for the vehicle.
It is, therefore, a still further object of this invention to provide an improved system for lubricating an auxiliary transmission.
It is another object of this invention to provide a lubricating system for an auxiliary transmission that is supplied with lubricant from the primary transmission which drives it.
When an auxiliary transmission is lubricated with the lubricant from the primary transmission, it is desirable if the entire lubricant can be drained by merely draining the primary transmission. However, it is also desirable to maintain a certain predetermined level of lubricant in the auxiliary transmission during running so as to insure that its gears will be properly lubricated. With prior art constructions, it has not been possible to achieve both of these ends.
It is, therefore, a further object of this invention to provide an improved lubricant system for an auxiliary transmission.
It is another object of this invention to provide a lubricant system of an auxiliary transmission wherein the lubricant level is maintained at a high level during running and at a substantially lower level with the transmission is not being driven.